A certificate of deposit [CD] is like giving the bank a loan on interest and is forbidden. The interest accrued must be given away in charity with no intent of reward, and Zakāh is due on the total amount every year if it exceeds the minimum amount [niṣāb]. It is recommended to pay Zakāh on this money yearly from other liquid funds you own. However, it will technically only become a requirement at maturity when you are able to access the money, and Zakāh must be paid on it for all previous unpaid years.
There is a misunderstanding that Zakah is only due when you have money in your physical possession or access to it. This is because books on Islamic Law state that ownership and possession are conditions for Zakah to be due. However, these statements should not be taken so literally and must be understood in proper context. Here is one example where context changes the understanding: “(From the conditions for the obligation of Zakat is having complete control over the wealth), and that means to have ownership and possession. If one has ownership of the wealth and not possession…or possession and not ownership…, then zakat will not be obligatory…if the commodity that has not yet been delivered is concerned….it will be part of the Nisab hence zakat will be obligatory on it according to the correct opinion.” (Al-Fatawa Al-Hindiyya, 1:172) The last part clarified that if you paid for an item but the product has not yet been delivered, you must still pay Zakah on it. So if I purchase a computer to resell for $3000 and it will be built and delivered in a month, I do not deduct the $3000 from my savings and pay no Zakah on the item I will be getting.